| /* $Id: fault.c,v 1.59 2002/02/09 19:49:31 davem Exp $ |
| * arch/sparc64/mm/fault.c: Page fault handlers for the 64-bit Sparc. |
| * |
| * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu) |
| * Copyright (C) 1997, 1999 Jakub Jelinek (jj@ultra.linux.cz) |
| */ |
| |
| #include <asm/head.h> |
| |
| #include <linux/string.h> |
| #include <linux/types.h> |
| #include <linux/sched.h> |
| #include <linux/ptrace.h> |
| #include <linux/mman.h> |
| #include <linux/signal.h> |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/smp_lock.h> |
| #include <linux/init.h> |
| #include <linux/interrupt.h> |
| #include <linux/kprobes.h> |
| |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| #include <asm/openprom.h> |
| #include <asm/oplib.h> |
| #include <asm/uaccess.h> |
| #include <asm/asi.h> |
| #include <asm/lsu.h> |
| #include <asm/sections.h> |
| #include <asm/kdebug.h> |
| |
| #define ELEMENTS(arr) (sizeof (arr)/sizeof (arr[0])) |
| |
| extern struct sparc_phys_banks sp_banks[SPARC_PHYS_BANKS]; |
| |
| /* |
| * To debug kernel to catch accesses to certain virtual/physical addresses. |
| * Mode = 0 selects physical watchpoints, mode = 1 selects virtual watchpoints. |
| * flags = VM_READ watches memread accesses, flags = VM_WRITE watches memwrite accesses. |
| * Caller passes in a 64bit aligned addr, with mask set to the bytes that need to be |
| * watched. This is only useful on a single cpu machine for now. After the watchpoint |
| * is detected, the process causing it will be killed, thus preventing an infinite loop. |
| */ |
| void set_brkpt(unsigned long addr, unsigned char mask, int flags, int mode) |
| { |
| unsigned long lsubits; |
| |
| __asm__ __volatile__("ldxa [%%g0] %1, %0" |
| : "=r" (lsubits) |
| : "i" (ASI_LSU_CONTROL)); |
| lsubits &= ~(LSU_CONTROL_PM | LSU_CONTROL_VM | |
| LSU_CONTROL_PR | LSU_CONTROL_VR | |
| LSU_CONTROL_PW | LSU_CONTROL_VW); |
| |
| __asm__ __volatile__("stxa %0, [%1] %2\n\t" |
| "membar #Sync" |
| : /* no outputs */ |
| : "r" (addr), "r" (mode ? VIRT_WATCHPOINT : PHYS_WATCHPOINT), |
| "i" (ASI_DMMU)); |
| |
| lsubits |= ((unsigned long)mask << (mode ? 25 : 33)); |
| if (flags & VM_READ) |
| lsubits |= (mode ? LSU_CONTROL_VR : LSU_CONTROL_PR); |
| if (flags & VM_WRITE) |
| lsubits |= (mode ? LSU_CONTROL_VW : LSU_CONTROL_PW); |
| __asm__ __volatile__("stxa %0, [%%g0] %1\n\t" |
| "membar #Sync" |
| : /* no outputs */ |
| : "r" (lsubits), "i" (ASI_LSU_CONTROL) |
| : "memory"); |
| } |
| |
| static void __kprobes unhandled_fault(unsigned long address, |
| struct task_struct *tsk, |
| struct pt_regs *regs) |
| { |
| if ((unsigned long) address < PAGE_SIZE) { |
| printk(KERN_ALERT "Unable to handle kernel NULL " |
| "pointer dereference\n"); |
| } else { |
| printk(KERN_ALERT "Unable to handle kernel paging request " |
| "at virtual address %016lx\n", (unsigned long)address); |
| } |
| printk(KERN_ALERT "tsk->{mm,active_mm}->context = %016lx\n", |
| (tsk->mm ? |
| CTX_HWBITS(tsk->mm->context) : |
| CTX_HWBITS(tsk->active_mm->context))); |
| printk(KERN_ALERT "tsk->{mm,active_mm}->pgd = %016lx\n", |
| (tsk->mm ? (unsigned long) tsk->mm->pgd : |
| (unsigned long) tsk->active_mm->pgd)); |
| if (notify_die(DIE_GPF, "general protection fault", regs, |
| 0, 0, SIGSEGV) == NOTIFY_STOP) |
| return; |
| die_if_kernel("Oops", regs); |
| } |
| |
| static void bad_kernel_pc(struct pt_regs *regs) |
| { |
| unsigned long *ksp; |
| |
| printk(KERN_CRIT "OOPS: Bogus kernel PC [%016lx] in fault handler\n", |
| regs->tpc); |
| __asm__("mov %%sp, %0" : "=r" (ksp)); |
| show_stack(current, ksp); |
| unhandled_fault(regs->tpc, current, regs); |
| } |
| |
| /* |
| * We now make sure that mmap_sem is held in all paths that call |
| * this. Additionally, to prevent kswapd from ripping ptes from |
| * under us, raise interrupts around the time that we look at the |
| * pte, kswapd will have to wait to get his smp ipi response from |
| * us. This saves us having to get page_table_lock. |
| */ |
| static unsigned int get_user_insn(unsigned long tpc) |
| { |
| pgd_t *pgdp = pgd_offset(current->mm, tpc); |
| pud_t *pudp; |
| pmd_t *pmdp; |
| pte_t *ptep, pte; |
| unsigned long pa; |
| u32 insn = 0; |
| unsigned long pstate; |
| |
| if (pgd_none(*pgdp)) |
| goto outret; |
| pudp = pud_offset(pgdp, tpc); |
| if (pud_none(*pudp)) |
| goto outret; |
| pmdp = pmd_offset(pudp, tpc); |
| if (pmd_none(*pmdp)) |
| goto outret; |
| |
| /* This disables preemption for us as well. */ |
| __asm__ __volatile__("rdpr %%pstate, %0" : "=r" (pstate)); |
| __asm__ __volatile__("wrpr %0, %1, %%pstate" |
| : : "r" (pstate), "i" (PSTATE_IE)); |
| ptep = pte_offset_map(pmdp, tpc); |
| pte = *ptep; |
| if (!pte_present(pte)) |
| goto out; |
| |
| pa = (pte_val(pte) & _PAGE_PADDR); |
| pa += (tpc & ~PAGE_MASK); |
| |
| /* Use phys bypass so we don't pollute dtlb/dcache. */ |
| __asm__ __volatile__("lduwa [%1] %2, %0" |
| : "=r" (insn) |
| : "r" (pa), "i" (ASI_PHYS_USE_EC)); |
| |
| out: |
| pte_unmap(ptep); |
| __asm__ __volatile__("wrpr %0, 0x0, %%pstate" : : "r" (pstate)); |
| outret: |
| return insn; |
| } |
| |
| extern unsigned long compute_effective_address(struct pt_regs *, unsigned int, unsigned int); |
| |
| static void do_fault_siginfo(int code, int sig, struct pt_regs *regs, |
| unsigned int insn, int fault_code) |
| { |
| siginfo_t info; |
| |
| info.si_code = code; |
| info.si_signo = sig; |
| info.si_errno = 0; |
| if (fault_code & FAULT_CODE_ITLB) |
| info.si_addr = (void __user *) regs->tpc; |
| else |
| info.si_addr = (void __user *) |
| compute_effective_address(regs, insn, 0); |
| info.si_trapno = 0; |
| force_sig_info(sig, &info, current); |
| } |
| |
| extern int handle_ldf_stq(u32, struct pt_regs *); |
| extern int handle_ld_nf(u32, struct pt_regs *); |
| |
| static unsigned int get_fault_insn(struct pt_regs *regs, unsigned int insn) |
| { |
| if (!insn) { |
| if (!regs->tpc || (regs->tpc & 0x3)) |
| return 0; |
| if (regs->tstate & TSTATE_PRIV) { |
| insn = *(unsigned int *) regs->tpc; |
| } else { |
| insn = get_user_insn(regs->tpc); |
| } |
| } |
| return insn; |
| } |
| |
| static void do_kernel_fault(struct pt_regs *regs, int si_code, int fault_code, |
| unsigned int insn, unsigned long address) |
| { |
| unsigned char asi = ASI_P; |
| |
| if ((!insn) && (regs->tstate & TSTATE_PRIV)) |
| goto cannot_handle; |
| |
| /* If user insn could be read (thus insn is zero), that |
| * is fine. We will just gun down the process with a signal |
| * in that case. |
| */ |
| |
| if (!(fault_code & (FAULT_CODE_WRITE|FAULT_CODE_ITLB)) && |
| (insn & 0xc0800000) == 0xc0800000) { |
| if (insn & 0x2000) |
| asi = (regs->tstate >> 24); |
| else |
| asi = (insn >> 5); |
| if ((asi & 0xf2) == 0x82) { |
| if (insn & 0x1000000) { |
| handle_ldf_stq(insn, regs); |
| } else { |
| /* This was a non-faulting load. Just clear the |
| * destination register(s) and continue with the next |
| * instruction. -jj |
| */ |
| handle_ld_nf(insn, regs); |
| } |
| return; |
| } |
| } |
| |
| /* Is this in ex_table? */ |
| if (regs->tstate & TSTATE_PRIV) { |
| const struct exception_table_entry *entry; |
| |
| if (asi == ASI_P && (insn & 0xc0800000) == 0xc0800000) { |
| if (insn & 0x2000) |
| asi = (regs->tstate >> 24); |
| else |
| asi = (insn >> 5); |
| } |
| |
| /* Look in asi.h: All _S asis have LS bit set */ |
| if ((asi & 0x1) && |
| (entry = search_exception_tables(regs->tpc))) { |
| regs->tpc = entry->fixup; |
| regs->tnpc = regs->tpc + 4; |
| return; |
| } |
| } else { |
| /* The si_code was set to make clear whether |
| * this was a SEGV_MAPERR or SEGV_ACCERR fault. |
| */ |
| do_fault_siginfo(si_code, SIGSEGV, regs, insn, fault_code); |
| return; |
| } |
| |
| cannot_handle: |
| unhandled_fault (address, current, regs); |
| } |
| |
| asmlinkage void __kprobes do_sparc64_fault(struct pt_regs *regs) |
| { |
| struct mm_struct *mm = current->mm; |
| struct vm_area_struct *vma; |
| unsigned int insn = 0; |
| int si_code, fault_code; |
| unsigned long address; |
| |
| fault_code = get_thread_fault_code(); |
| |
| if (notify_die(DIE_PAGE_FAULT, "page_fault", regs, |
| fault_code, 0, SIGSEGV) == NOTIFY_STOP) |
| return; |
| |
| si_code = SEGV_MAPERR; |
| address = current_thread_info()->fault_address; |
| |
| if ((fault_code & FAULT_CODE_ITLB) && |
| (fault_code & FAULT_CODE_DTLB)) |
| BUG(); |
| |
| if (regs->tstate & TSTATE_PRIV) { |
| unsigned long tpc = regs->tpc; |
| |
| /* Sanity check the PC. */ |
| if ((tpc >= KERNBASE && tpc < (unsigned long) _etext) || |
| (tpc >= MODULES_VADDR && tpc < MODULES_END)) { |
| /* Valid, no problems... */ |
| } else { |
| bad_kernel_pc(regs); |
| return; |
| } |
| } |
| |
| /* |
| * If we're in an interrupt or have no user |
| * context, we must not take the fault.. |
| */ |
| if (in_atomic() || !mm) |
| goto intr_or_no_mm; |
| |
| if (test_thread_flag(TIF_32BIT)) { |
| if (!(regs->tstate & TSTATE_PRIV)) |
| regs->tpc &= 0xffffffff; |
| address &= 0xffffffff; |
| } |
| |
| if (!down_read_trylock(&mm->mmap_sem)) { |
| if ((regs->tstate & TSTATE_PRIV) && |
| !search_exception_tables(regs->tpc)) { |
| insn = get_fault_insn(regs, insn); |
| goto handle_kernel_fault; |
| } |
| down_read(&mm->mmap_sem); |
| } |
| |
| vma = find_vma(mm, address); |
| if (!vma) |
| goto bad_area; |
| |
| /* Pure DTLB misses do not tell us whether the fault causing |
| * load/store/atomic was a write or not, it only says that there |
| * was no match. So in such a case we (carefully) read the |
| * instruction to try and figure this out. It's an optimization |
| * so it's ok if we can't do this. |
| * |
| * Special hack, window spill/fill knows the exact fault type. |
| */ |
| if (((fault_code & |
| (FAULT_CODE_DTLB | FAULT_CODE_WRITE | FAULT_CODE_WINFIXUP)) == FAULT_CODE_DTLB) && |
| (vma->vm_flags & VM_WRITE) != 0) { |
| insn = get_fault_insn(regs, 0); |
| if (!insn) |
| goto continue_fault; |
| if ((insn & 0xc0200000) == 0xc0200000 && |
| (insn & 0x1780000) != 0x1680000) { |
| /* Don't bother updating thread struct value, |
| * because update_mmu_cache only cares which tlb |
| * the access came from. |
| */ |
| fault_code |= FAULT_CODE_WRITE; |
| } |
| } |
| continue_fault: |
| |
| if (vma->vm_start <= address) |
| goto good_area; |
| if (!(vma->vm_flags & VM_GROWSDOWN)) |
| goto bad_area; |
| if (!(fault_code & FAULT_CODE_WRITE)) { |
| /* Non-faulting loads shouldn't expand stack. */ |
| insn = get_fault_insn(regs, insn); |
| if ((insn & 0xc0800000) == 0xc0800000) { |
| unsigned char asi; |
| |
| if (insn & 0x2000) |
| asi = (regs->tstate >> 24); |
| else |
| asi = (insn >> 5); |
| if ((asi & 0xf2) == 0x82) |
| goto bad_area; |
| } |
| } |
| if (expand_stack(vma, address)) |
| goto bad_area; |
| /* |
| * Ok, we have a good vm_area for this memory access, so |
| * we can handle it.. |
| */ |
| good_area: |
| si_code = SEGV_ACCERR; |
| |
| /* If we took a ITLB miss on a non-executable page, catch |
| * that here. |
| */ |
| if ((fault_code & FAULT_CODE_ITLB) && !(vma->vm_flags & VM_EXEC)) { |
| BUG_ON(address != regs->tpc); |
| BUG_ON(regs->tstate & TSTATE_PRIV); |
| goto bad_area; |
| } |
| |
| if (fault_code & FAULT_CODE_WRITE) { |
| if (!(vma->vm_flags & VM_WRITE)) |
| goto bad_area; |
| |
| /* Spitfire has an icache which does not snoop |
| * processor stores. Later processors do... |
| */ |
| if (tlb_type == spitfire && |
| (vma->vm_flags & VM_EXEC) != 0 && |
| vma->vm_file != NULL) |
| set_thread_fault_code(fault_code | |
| FAULT_CODE_BLKCOMMIT); |
| } else { |
| /* Allow reads even for write-only mappings */ |
| if (!(vma->vm_flags & (VM_READ | VM_EXEC))) |
| goto bad_area; |
| } |
| |
| switch (handle_mm_fault(mm, vma, address, (fault_code & FAULT_CODE_WRITE))) { |
| case VM_FAULT_MINOR: |
| current->min_flt++; |
| break; |
| case VM_FAULT_MAJOR: |
| current->maj_flt++; |
| break; |
| case VM_FAULT_SIGBUS: |
| goto do_sigbus; |
| case VM_FAULT_OOM: |
| goto out_of_memory; |
| default: |
| BUG(); |
| } |
| |
| up_read(&mm->mmap_sem); |
| return; |
| |
| /* |
| * Something tried to access memory that isn't in our memory map.. |
| * Fix it, but check if it's kernel or user first.. |
| */ |
| bad_area: |
| insn = get_fault_insn(regs, insn); |
| up_read(&mm->mmap_sem); |
| |
| handle_kernel_fault: |
| do_kernel_fault(regs, si_code, fault_code, insn, address); |
| return; |
| |
| /* |
| * We ran out of memory, or some other thing happened to us that made |
| * us unable to handle the page fault gracefully. |
| */ |
| out_of_memory: |
| insn = get_fault_insn(regs, insn); |
| up_read(&mm->mmap_sem); |
| printk("VM: killing process %s\n", current->comm); |
| if (!(regs->tstate & TSTATE_PRIV)) |
| do_exit(SIGKILL); |
| goto handle_kernel_fault; |
| |
| intr_or_no_mm: |
| insn = get_fault_insn(regs, 0); |
| goto handle_kernel_fault; |
| |
| do_sigbus: |
| insn = get_fault_insn(regs, insn); |
| up_read(&mm->mmap_sem); |
| |
| /* |
| * Send a sigbus, regardless of whether we were in kernel |
| * or user mode. |
| */ |
| do_fault_siginfo(BUS_ADRERR, SIGBUS, regs, insn, fault_code); |
| |
| /* Kernel mode? Handle exceptions or die */ |
| if (regs->tstate & TSTATE_PRIV) |
| goto handle_kernel_fault; |
| } |